(1) Field of the Invention
This invention relates to a carburetor having an acceleration pump. More particularly, the invention relates to a carburetor having an acceleration pump in which the amount of fuel injected into the fuel-air mixture chamber is adjusted to conform more closely with the rotation rate of the engine.
(2) Description of the Prior Art
In an acceleration pump of a carburetor for preventing an acceleration lag in an automobile, the piston of the acceleration pump acting with the throttle valve is moved vertically to inject fuel contained in a cylinder into the fuel-air mixture chamber of the carburetor through an injection channel and an restrictor mounted in the end of the injection channel. According to this conventional method, the rate of fuel injection is determined exclusively by the force on the piston, and hence, it is impossible to control and adjust the amount of fuel injected in accordance with the rate of rotation of the internal-combustion engine.
More specifically, since injection of fuel is conducted regardless of the rate of rotation of the engine whether at the initial injector stage at a low rate of rotation or at the later injection stage at a high rate of rotation, an excess of fuel is injected at the initial stage and the injection of fuel is insufficient at the later stage. Because of this defect, improvement of the accelerating capacity is limited, and at the initial stage incomplete combustion is caused owing to excessive injection of fuel. Harmful gases such as CO and hydrocarbons are generated by this incomplete combustion.